Solution for roto moulding

LARGE-VOLUME products are almost by definition suited to
rotational moulding, and like any other plastics production process,
rotomoulding has advantages and disadvantages.The process is particularly suited to large volume products because
mould construction costs are lower and the production equipment used – due to
the lower pressures employed (as opposed to blow or injection moulding) – involves a lower capex too.But at the
same time, mould residence times are longer and control of heating, cooling and
demoulding are more complicated.

Rotationally moulded products are supposed to be
stress-free, but this only happens when the moulding is properly cured and
cooled.For example, a 5 000 or 10 000
litre water tank can look superb on leaving the mould, but warping and cracking
can easily result once out in the African sun if curing and cooling has not
been effectively managed.

Temperature within the mould has historically been one of
the problems for rotomoulders: excessive temperatures over stress the material,
and when temperatures are too low, the material can be under cured.

And then the question is: when is the right time to
demould?Too soon and the product is
under cured, too late and it's over cured.Either scenario results in a higher risk of the product failing in the
field. Permutations of these criteria are what keep rotomoulders guessing, a
lot of the time.

Developing a system to effectively control this process has
long been a need in the rotomoulding industry and one person who's had a
lasting passion to overcome the problem is Gary Lategan of Roto Solutions in
Klerksdorp, South Africa.It's one of
the few problems Gary has not completely solved yet. He's been involved in the
rotomoulding industry for over two decades with Atlas Plastics, during which
time he's developed production systems for just about every type of
rotomoulding imaginable.Atlas
Plastics, which is now run by his brothers Rene and Pierre, manufactures about
2 500 rotomoulded products daily, including tanks, basins, toilets, mining
components and a host of other products.

Gary was closely involved in the design and development of many, if not all, of the production systems for these products. Eventually the challenge moved on to another level, which led to the formation in 2004 of Roto Solutions, which was set up across the road from Atlas Plastics in Klerksdorp.

Roto Solutions is a R + D company focused on innovation for the rotomoulding industry, its main focus being on temperature control for which the TempLogger™ temperature monitoring and control package was developed, and mould release for which Roto Khulula™ was introduced.

The problem of temperature

Temperature logging for the rotational moulding industry has been developing over the past six years. Queens University of Belfast, Northern Ireland, a leading research centre for the rotomoulding industry globally, was first off the mark with its Rotolog™ system.The system was functional, but did not fully meet Gary's requirements.What he required was a simple and easy-to-use real-time temperature measurement system giving the ability to effectively manage rotomoulding production in the least time.

Gary Lategan of Roto Solutions has been involved in rotomoulding for over 20 years

What he saw was a diagnostic tool to optimize heating and
cooling cycles and allow operators to identify faults immediately, thereby
reducing rejects and operational delays. So, after a five-year development
period reaching fruition in mid-2004, the first version of the TempLogger was
introduced in August 2004. The package has evolved constantly since then, with
the fourth version just released.

The system consists of three basic components: a control station
on PC or laptop, a base unit and a sender unit. The control station communicates with the base unit that
communicates with the sender unit on a wireless basis. Thermocouple sensors are attached to the
sender unit to measure oven and internal mould temperatures.It can monitor temperatures over a range of -20°C to 550°C
with a variance of just 2°C. Continuous, real-time monitoring of multiple
stations – recording temperatures by machine, product, date and time – is
achieved.

The result is: greatly reduced incidence of rejects from over or
under cure or due to sticking in mould because of shrinkage.Gary's jovial manner and enthusiasm, plus his liking to do
as much as possible in-house (in typical boer
maak ‘n plan mode), may have hidden a deeper resolve, but the technical and
scientific demands of the development process have brought out a more expansive
vision from him. No rotomoulding problem is too much for Gary – this man has a
serious passion for the process and continuously looking at how to improve the
process.Some of the top rotomoulding specialists have trekked out to
Klerksdorp in North West province and been amazed by the abilities and scale of
control achieved by TempLogger.

Latest version

The latest version of TempLogger includes recipes and alarm
settings to control oven operation and cooling cycles based on internal mould
temperatures.Guideline graphs for each
product closely track expected temperatures, assisting with moulding operations
and cycle times. The system can also be used for R + D while in production or
as a standalone monitor.